View Full Version : X-STAR 2004 MCX TWIN FORK FUEL PUMP AGAIN 323 # 4D03C Carter

05-15-2011, 05:57 AM
Hi guys,

Been on the river today, sesh not so good ended up with boat starting and then cutting off and a tow back to the shore by a fishermen boat ;)))

Anyway, thought it was my dual battery guest isolator, removed it and connected cables together and it is not that.

Obviously it must have been the fuel pump (as my friend advised)

took it out - tried it in the pint glass - it works but does not suck ;P

http://img844.imageshack.us/img844/4421/ed1l.th.jpg (http://imageshack.us/photo/my-images/844/ed1l.jpg/)

read all the threads about fuel pumps from a-z with airtex and nada replacements option and it seems that I might need an Airtex 2044 or something else

I found this that delivers up to 60 PSI and it seems very similiar if not exactly the same:


Do you think that this will turbo my boat up?

IF NOT - please WHAT - not paying stealership prices in Australia of over $1000 for MC Carter **** which broke

Also - need the 2 filters that are fitted - one big below the pump and one under the pump - any recommendations for that - some online shop or maybe even ebay.

Meanwhile I am gonna have a drive round tomorrow to see if the auto shops sell something similiar.

Please help BOYS AND GIRLS - you have been brilliant so far!!!

05-16-2011, 01:37 AM
Hey guys, I went to FUEL PUMP SHOP locally and they said the following

1. MC fuel pump was bound to fail as 2 filters is to much and pump pushes fuel better than sucks
2. Buy a bigger BOSCH PUMP for 600bhp V8 Audi engine for 260 bucks and retrofit it
3. Bosch pump is not only bigger but has a inbuilt filter in it and will last forever
4. Put a proper Fuel Filter on the hose (the red one that comes out of tank)
5. Forget about MC filters

Bosch pump has bigger outlet so wont fit the black fuel hose that runs from the pump to the regurgitator ;)

it will not fit nice and tighht in the container.

WHO thinks it will do the job ????

Who thinks it will do the job???

Please help guys!!

If I fit it I will try to put part numbers and photos

05-16-2011, 05:23 AM
I have a cheap Chinese fuel pump and it works fine.

Actually, it is so cheap, I bought two of them, just for security.


I used the filter equipped with the kit, because the Mastercraft container/float setup does not work like I think it should work IMHO.

05-16-2011, 07:08 AM
hey man, you are right it is an option I am considering as well, I looked at the very similar pump that pumps out 60psi but on the other hand maybe its a good idea to buy a super duper Bosch pump and retrofit in the original bucket and put a fuel filter on the high press hose. Easy to change, no messing about and pump will exceed the life of the boat.

05-17-2011, 03:39 AM
fitted the pump 10 minutes ago and it works, engine start incredibly quick, need to fit it more properly tomorrow and screw it all in and fit a fuel filter on the red pipe, well try to update with photos.

05-17-2011, 05:31 AM
Hurry up and get those pics up Cobb!!!

05-17-2011, 07:08 AM
had to finish as had a meet 5-9 but tested it with new pump rated for 600 bhp and shet loads of psi and works.

will probably put factory filter on the top on what is on the pump and put a HD diesel filter on red hose tomorrow and put some photos up.

I am so excited as I dont think anyone tried that before.

The only thing is that this pump is not 100% secured in the plastic bucket but I dont see this as a problem.

DOES anyone think this could cause dramas?

05-18-2011, 01:22 AM
http://img705.imageshack.us/img705/4272/fuelpump011.th.jpg (http://img705.imageshack.us/i/fuelpump011.jpg/)

The connection at the top via original pipe and pliers clamp

http://img809.imageshack.us/img809/3909/fuelpump009.th.jpg (http://img809.imageshack.us/i/fuelpump009.jpg/)

connection at the bottom is screw on the pump and then put onto a clamp still via original cable
http://img233.imageshack.us/img233/2381/fuelpump010.th.jpg (http://img233.imageshack.us/i/fuelpump010.jpg/)

05-18-2011, 01:26 AM
Fuel Filter to be fitted onto the original hose

http://img863.imageshack.us/img863/1056/fuelpump008.th.jpg (http://img863.imageshack.us/i/fuelpump008.jpg/)

05-26-2011, 04:36 AM
All fitted - big problem with factory hose - leaked when fitted on filter - had to buy new one and fit it with screw brackets - not sure if this is safe enough. Tested on the water fo 30 mins and seems good

Guessing will have to keep eye out on it.

The pump works beautifully I have to say though - really happy - would not have fitted original one again.

05-30-2011, 07:23 PM
Innovative solution! Should have gone with the fuel pump of an S8 though..;)...kidding...

I am a little worried about the bottom of the pump not being secure. You didn't show a pic of the pump inlet. When i did mine the pump inlet was secured in the bottom of the module so that it didn't move or flop around. Is yours just floating free in the bottom of the module above the filter?
Which replacement hose did you go with? Why do you think that it would be a saftey issue?
I love the aftermarket fuel filter idea, but am confused as to where you are putting it.

05-30-2011, 07:37 PM
hey mate, the s8 might use that pump as on the box - porsche, bmw, audi with no specific tags ;)

bottom of the pump is not secured - true - It is doable but this pump is slightly bigger and it sits there quite tight anyhow - plus you have a black fuel line which is by no means flexy and that should hold it too. Apart from that - the pump sits in the place of the small fuel filter - which is still a bit bigger - but it will restrain the movement to minimum. I removed that small filter as Bosch has its own on the pump. This would not worry me too much as the worst that can happen is the pump can take off from the hose (not sure if that's the way to put it) Baiscally the small hose can disconnect itself from the pump (tho its secured via good clip on the top and its got a hydraulic fitting to the pump.

I could not take a photo whilst doing it as was covered in fuel from top to bottom - did not want to create a spark or damage the camera - 200 l of fuel below me ;)

HOSE - 180 Psi - but not a fire hose. You can put a red fire hose around it from the old hose I reckon - have not done that yet tho

The aftermarket fuel filter which is HD Diesel filter is fitted to the left wall of the engine bay in between the tank and engine. You gotta connect the hoses to it via fittings and then secure them onto fittings and engine and top of the tank. The problem for me was to secure these onto a filter. My fittings screw in the filter and despite I put teflon tape on them and heaps of it they were both leaking slightly from the thread. Corrected it like 5 times and put heaps of teflon tape on them and the leak stopped. We tested it twice now and no leaks whatsoever so seems pretty good.

I know I have to keep an eye on it or possibly change the brackets to some better ones etc.

I will also put a red sleeve on my 180 psi fuel line from the old fuel line - original on MC

What do you think?

05-30-2011, 09:50 PM
Ok...I think I was confused as to which hose you were talking about. I thought you talking about the hose between the fuel pressure regulator and the pump but I realize you mean the main line between the fuel module and the fuel rail..correct?

I never really thought about putting a filter there, but I guess it could hurt as long as you are getting the correct pressure and flow at the rail. Better check it with a gauge.

As long as the fuel filter doesn't affect the fuel pressure or volume between the regulator and the rail you should be fine.
Is there any filter before the actual pump and pressure regulator? You probably don't want any debris getting sucked up into either....

As far as the fire rating on the main line your guess is as good as mine.

05-30-2011, 10:03 PM
Hey bro,

Yeah the hose between the reg and pump seems ok - I have a replacement one in case that one brakes anyway

The pressure between the tank and the engine should be correct I believe - the filter will keep filling up and holding the pressure

The Bosch pump pumps in regions of 100 psi to 58 psi reg - as a result engine starts sweeter than ever - at the touch of the key, even if batteries are a bit down - previous to that I had to crank it for 2-3 secs. Now - its absolutely instant.

There are 3 filters in total now - one factory at the bottom of the tank, one on the pump and one in between the press reg and engine.

These pumps are designed to push , not to pull fuel - a fuel pump guy told me that MC design is bad as the fuel gets pulled through 2 filters - one is a really tiny one - he said no wonder these fail all the time. The more the pump pulls rather then pushes - the more strain is on the pump. He actually told me to remove the fuel filter all together and leave the built in one to do the preliminary filtering and the HD one after the tank to do the rest. Taking the reg into consideraiton and qulaity of fuel in Aus I decided to leave that one just in case.

Hows that?

05-30-2011, 10:52 PM
Sounds good.

I would just verify your fuel pressure at the rail both while at idle and under load. Just to be safe.

05-30-2011, 11:00 PM
How would you do that and what tools would I need not to break anything and I am not a mechanic or a very technical person either ;)

05-31-2011, 10:36 AM
You need a fuel pressure gauge. You can probably borrow one from someone. You install it on the schrader valve on the fuel rail, then start the motor. You should see 58 psi all the time, even under load.

05-31-2011, 05:48 PM
Seen one on ebay for 20 bux in the states, might give it a go at some time, thanks for your comments mate

06-01-2011, 05:45 AM
These pumps are designed to push , not to pull fuel - a fuel pump guy told me that MC design is bad as the fuel gets pulled through 2 filters - one is a really tiny one - he said no wonder these fail all the time. The more the pump pulls rather then pushes - the more strain is on the pump.
I highly doubt that. I spent an whole afternoon watching and trying to understand the stock fuel bucket setup from my Prostar. I add some litres gas in an bucket and played with the system.
The float is letting fuel going into the fuelpumpbucket/container. As soon as you make a turn with the boat, fuel in the tank is flowing away and the float in the fuelpumpbucket is closing the bucket, so the pump can suck fuel what stays in the bucket.
As soon as the fuel in the tank is going back to normal, the fuelpumpbucket is filling up again.
The fuel has to float through the filters, no mather if the pump is sucking or not.
The reason the pump is failing, I think, is because the fuelpumpcontainer design works only if the boattank is full enough. The floatsystem from the fuelpumpbucket is blocking off fuel as soon as fuellevel is at about . This is causing the fuel pump to run dry often enough to crash the fuelpump. Agreed, actually the pump should survive this, but the stock Carter does not. We have to deal with that.

What I did was modifying a big pipe and add my cheap Chinese pump with it's own filter.
Installed it as low as possible, and drilled some holes. This way the fuel is staying with the pump when cornering the boat.
Untill now still no problems, and I can drive the tank further empty with no probs.

If nothing is going wrong, I will take a look into the tank at the end of the season. I am very curious how things hold up.

The only thing I need to do is modify the breather system. I hate it to have an 119 liter tank what can take only 88 liter... :mad:



06-01-2011, 06:54 AM
hey mate, you might be right, as I said I am not a mechanic, but the info I got was from a fuel pump guru in town.

Also there will be major dif in X-star and prostar I reckon.

I like the way you did your setup - might be worth considering if mine one does not work

We are going for a 4 day weekend and I will pass my comments on return

06-17-2011, 08:21 PM
just a quick update - gone through about 150-175 litres of fuel and no problem whatsoever - engine starts really well - have not checked the psi yet but I will and all in all really happy with the upgrade - at this moment would recommend to anyone who wants to get rid of bad pumps - once in a boat life investment I reckon.
3 days of riding - tank nearly empty and no issues